As latch for switch tongues, for example, closures consisting of a blade mount, a rail mount, a latch pawl, and cam rods are well known and described (see DE 195 02 105 and EP 1 488 979 [U.S. Pat. No. 7,564,491]).
Installation and adjustment of the closures must be possible in a simple and fast manner. This requires a closure whose parts can be preset prior to installation in such a manner that complicated alignment of the closure during installation is eliminated.
In a solution known from EP 0 624 508, the rail mount is clamped to the foot of the stock rail. However, during assembly of the latch closure, in addition, the rail mount has to be readjusted in a complicated manner with a profile compensation rod to compensate for thickness tolerances of the stock rail foot. An additional adjustment of the distance between tongue and stock rail is carried out with an eccentric bolt located in the catch.
It is known from EP 0 723 901 and DE 195 02 105 to bolt rather than clamp the rail mount with the web of the stock rail. An additional adjustment is carried out by an eccentric and roller. With the eccentric, the distance between the cam rod and the bottom side of the stock rail foot can be adjusted. An additional is adjustment between the tongue and the stock rail is carried out analogously by an eccentric bolt located in the closure, as already described above. The main disadvantage of this solution is the bores in the stock rail. That is because the bores must be aligned with the bore in the tongue foot or tongue web (for fastening the blade mount). Otherwise, the result is a malfunction. In particular after changing the tongues, alignment of the bores can only be achieved with great effort. The roller has the disadvantage that it can wear circumferentially and thus has to be replaced after a certain operating time.